How to import brush sets?
Sculpt and Texture Paint brushes can be imported as any other thing you might want to import/export between .blend files (objects / meshes / materials etc.).


Create new Sculpt / Texture Paint brush. Adjust its settings (in particular, change its name for something recognizable). In example below the brushes' name starts from "export-Brush...".
Save file which will be used as library (you will import from it).
Open new file, navigate to File > Append, find your saved file. When Blender's file browser enters file's contents, choose Brush. 




Both Sculpt (default and non-default) and Texture Paint (only created by you) brushes will be stored there. You'll see there as many brush sets as there were  additionally created in the original file.




Note:


You can link brushes instead of appending if you want to avoid editing them.
You don't need to pack textures in the main file if image textures were used; they will be stored in the brush settings. Note though that if file with imported brushes will be moved somewhere (or texture file will change its location) you'll need to provide it with textures in order Blender to find them.